MTC refers to a communication scheme involving one or more machines. MTC is also called Machine-to-Machine (M2M) communication or Internet of Things (IoT). A machine is an entity that does not need direct human manipulation or intervention. For example, a user device such as a smartphone that can be automatically connected to a network and perform communication without a user's manipulation/intervention as well as a meter or automatic vending machine equipped with a mobile communication module may be an example of the machine. Such various exemplary machines will be referred to as MTC devices or User Equipments (UEs) in the present disclosure. That is, MTC means communication performed by one or more machines (i.e., MTC devices without human manipulation/intervention.
MTC may cover communication between MTC devices (e.g., Device-to-Device (D2D) communication) and communication between an MTC device and an MTC application server. For example, communication between an MTC device and an MTC application server may be communication between an automatic vending machine and a server, communication between a Point Of Sale (POS) device and a server, and communication between an electricity, gas, or water meter and a server. Besides, MTC-based applications may include security, transportation, health care, etc.